1. Description of the Invention
The present invention relates to the irrigation and fertilization of plants, and more particularly pertains to new and improved methods and apparatuses for effecting such irrigation and fertilization in a much more efficient manner and at a substantially reduced cost.
2. Description of the Prior Art
As can be appreciated, literally thousands of different techniques and devices have been developed which are designed to improve upon existing irrigation and fertilization processes for plants. These techniques and devices include utilizing open water channels which overflow into areas of cultivation. This particular method suffers from wastage due to evaporation. Other attempts at efficient irrigation have included the use of capillary wick systems, but these are impractical over large areas. Also, underground pipes with holes or intervals have been tried without much success. This latter arrangement has the disadvantage that the pipes can be blocked by plant root systems if the plants are remote from the pipes. Also, if fertilizer is dissolved or suspended in the irrigation water, some of the fertilizer along with the water will not reach the plants and this waste fertilizer only serves to fertilize weeds and other unwanted vegetation. Other more promising techniques investigated have been those that utilize injector devices which may be inserted directly into plant stems or proximate their root systems. These injectors, which are typically of a perforated or porous construction, may be directly connected to a pressurized source of liquid, such as water or a liquid fertilizer, and the liquid may then be forced into the plant stem or into the soil surrounding the roots.
The prior art is replete with examples of such injectors utilized in the pressurized watering or feeding of plants. For example, U.S. Pat. No. 349,874, which issued to J. Buhrer on Sept. 28, 1886, illustrates an early construction for an injector which was designed for carrying liquid or semi-liquid fertilizers to the roots of trees and to the lower soil strata. This early device essentially consisted of a pipe open at both ends and having perforated sides, and further having a cover for closing the upper end. The pipes were set in the ground with their upper ends approximately level with the ground surface, and the liquid could then be poured directly into the pipe whereby it would flow through the perforations to the plant root system. While the Buhrer device most likely functions in its desired manner, this type of injector feeder requires the constant attention of a user inasmuch as each injector must be continually refilled with liquid on a frequent basis. Further, this type of device is not designed to accurately meter the amount of liquid delivered to a plant, whereby a substantial loss of liquid may occur directly into the soil--especially in view of the fact that much of the liquid may never directly come into contact with a plant root system.
On Oct. 18, 1904, a patent was issued to O. Berger with the device disclosed therein being directed to an insecticide tube directly positionable in a plant stem. The Berger device consisted of a tube having lateral perforations and adapted to be inserted in the body or root of a plant, with a portion of the tube being designed to angulate upwardly externally of the plant and serving as a receptacle and feeder for the composition with which the tube is filled. As such, a continual supply of insecticide could be delivered interiorly of the plant. This type of device was most probably never utilized commercially inasmuch as it also requires constant attention on the part of a user. In this regard, the tube would have to be continually recharged with insecticide on a frequent basis and, coupled with the difficulty of inserting the tube in the plant, it would appear to be infeasible from a commercial standpoint.
In U.S. Pat. No. 1,401,386, which issued to G. Wooderry on Dec. 27, 1921, a more improved irrigating system is described. This patent notes the fact that irrigating from and through the top surface of soil is very inefficient. In discussing this problem, the disclosure notes that the soil must first be prepared properly before any irrigation from the surface can be commenced and also that it takes an enormous amount of water to irrigate from the surface down to the roots of plants. In attempting to reduce the amount of water required for such irrigation, the Woodberry device includes the positioning beneath the soil surface of a conduit through which a supply of water may be delivered. Spaced at intervals along the conduit are porous concrete or mortar members which include interior hollow chambers. The supplied water is directed into these interior chambers and seeps outwardly through the porous walls into the soil so as to effect the desired irrigation. In an alternative embodiment, Woodberry dispenses with the individual porous containers and relies instead upon a continuous length of porous conduit, which is embedded in the soil. While this apparatus and method more accurately controls the amount and distribution of water to plants, again no provision is made to deliver exactly the amount of water needed by a plant and as such, a substantial amount of water is wasted.
Continuing with a discussion of the state of the art of plant injectors, reference is made to British Pat. No. 177,426, which issued to E. Burnet on Mar. 30, 1922. The Burnet device includes a nail which may be driven into a tree trunk, with such nail having a hollow tube concentrically positioned around its shank. As such, the hollow tube is also driven into the tree trunk with the nail, and the nail may then be removed to leave the hollow tube in the trunk. Burnet noted that liquids of a stimulating or nutritive character could then be poured into the hollow tube for introduction into the plant system. Again, however, this type of device requires constant attention on the part of the user and is, as such, difficult to use and impractical.
In a continuing effort to improve these similar methods of irrigation and fertilization, British Pat. No. 457,083 was issued to O. Stelzel on Nov. 20, 1936. The Stelzel device consisted essentially of a plurality of injectors attached to a common conduit having a pressurized water supply therein. The individual injectors include lower perforated sections through which water may be ejected, and a plurality of the injectors could then be circuitously positioned about a plant and driven into the soil proximate the plant's root system. This type of device constituted an attempt to more evenly distribute the water supply about a plant root system, but it also suffered from the problem of not being able to provide precisely the amount of water needed or being able to particularly insure that the water was distributed evenly to the complete root system.
In U.S. Pat. No. 3,758,987, which issued to W. Crane on Sept. 18, 1973, there is disclosed an automatic plant watering device which is described as being responsive to a plant's need for water. The device includes a porous element that is inserted into the soil proximate a plant root system and responds to the moisture content of the soil to control the supply of water from a substantially airtight enclosure. The porous element is of a wafer-like construction and may be typically formed from a porous ceramic material. Water will seep through the porous filter element when the soil is dry; however, this type of watering action does not necessarily respond to the amount of water needed by the particular plant and further, much water is then wasted since it is delivered directly to the soil and not the plant.
Another patent of interest with respect to injector devices is U.S. Pat. No. 3,992,813, which issued to Freshel on Nov. 23, 1976. The system disclosed in this patent comprises a plurality of injector assemblies, with each injector essentially consisting of a pipe insertible in an opening in a tree. Hoses may be attached to the individual injectors, and the hoses may then be utilized to connect various pressurized liquid fungicide containers to the injectors. As such, a pressurized feeding of a liquid fungicide into the tree system can be effected. The invention disclosed in this patent, as with most of the above-discussed inventions, relies upon the forced pressurized injection of a liquid into a plant system and is not designed to deliver only that amount of liquid as is actually needed.
In summary, the above review of the state of the art reveals that none of the currently known injector arrangements are designed to deliver only that amount of liquid to a plant which the plant actually requires. It is interesting to note that where the injector assemblies are positioned in the soil proximate a plant root system, up to 99.5 percent or more of the liquid may be wasted since only a very small amount of the liquid will be absorbed into the plant. Where the injectors are inserted directly into a plant stem, the pressurized feeding of the liquid may result in damage to the plant since too much liquid may be delivered thereto. Accordingly, it is apparent that there is a continuing need for improvements in the methods and apparatuses of the prior art whereby a more precise delivery of liquid to a plant could be accomplished, and in this respect, the present invention substantially fulfills this need.